Create ghost character from a certain point in cloth simulation
When I run the cloth simulation, I eventually get the ghost shape that I want.

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How do I &quot;pause&quot; it at the ghost shape that I want

Part 1.
 Go to the frame you want and make sure the cloth settings are perfect. This change will be permanent.  Go to your modifiers panel and click Apply.
 This will convert it from a dynamic modifier into an editable mesh.

Now, I want to add some actions for it.

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I want and start making animations for it, like Idle (I want the cloth to swing around a bit, like the ghost is swinging its hips) and Walk (I want the cloth to flow back like it's walking).

Part 2.
Next you'll want to rig the ghost. An armature system is a complex topic but I'll give you the basics.
 Start by adding a bone to your ghost.
 Enable X-ray so you can see what you're doing
 Making sure your bone is positioned at the top of the ghost hit TAB to go into edit mode and E to extrude it down once.
 Back in object mode select your ghost, hold down SHIFT and then select your armature you just created. Press CTRL and P to bring up the menu in the illustration.
 Finally animate the ghost how you like it to look.
Here's a GIF of what I came up with:
 Not bad for simple it was to create. More bones gives you more control obviously.